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422 giacomo 1
#ifndef __I386_DIV64
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#define __I386_DIV64
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/*
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 * do_div() is NOT a C function. It wants to return
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 * two values (the quotient and the remainder), but
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 * since that doesn't work very well in C, what it
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 * does is:
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 *
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 * - modifies the 64-bit dividend _in_place_
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 * - returns the 32-bit remainder
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 *
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 * This ends up being the most efficient "calling
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 * convention" on x86.
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 */
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#define do_div(n,base) ({ \
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        unsigned long __upper, __low, __high, __mod, __base; \
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        __base = (base); \
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        asm("":"=a" (__low), "=d" (__high):"A" (n)); \
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        __upper = __high; \
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        if (__high) { \
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                __upper = __high % (__base); \
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                __high = __high / (__base); \
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        } \
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        asm("divl %2":"=a" (__low), "=d" (__mod):"rm" (__base), "0" (__low), "1" (__upper)); \
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        asm("":"=A" (n):"a" (__low),"d" (__high)); \
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        __mod; \
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})
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/*
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 * (long)X = ((long long)divs) / (long)div
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 * (long)rem = ((long long)divs) % (long)div
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 *
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 * Warning, this will do an exception if X overflows.
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 */
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#define div_long_long_rem(a,b,c) div_ll_X_l_rem(a,b,c)
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extern inline long
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div_ll_X_l_rem(long long divs, long div, long *rem)
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{
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        long dum2;
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      __asm__("divl %2":"=a"(dum2), "=d"(*rem)
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      : "rm"(div), "A"(divs));
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        return dum2;
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}
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#endif